In Live Right Dr. D recommends Os avoid kava kava, as it 'can significantly inhibit platelet MAO' (and we Os tend to be low in MAO as it is).

You might give valerian a try. I take about 500 mg a night along with some magnesium, and sleep pretty well. If I do wake, it's much easier for me to get back to sleep. Valerian works gently and no side effects that I've found, though some people here have reported that it helps them get to sleep but not stay asleep.